Door latch assembly for side door discharge bins

ABSTRACT

A LATCH ASSEMBLY FOR A HINGED SIDE DOOR IN A BIN FOR BULK MATERIALS WHEREIN A SPLIT SLEEVE IS ASSEMBLED WITH A LATCH BOLT SO THAT WHEN THE DOOR IS LATCHED, A TIGHT SEAL IS PROVIDED AROUND THE LATCH BOLT TO PREVENT LEAKAGE OF THE BIN CONTENTS.

March 2, 1971 R. E. MC Y 3,567,263

DOOR LATCH ASSEMBLY FOR SIDE DOOR DISCHARGE BI NS Filed Nov. 29, 1968 INVENTOR RALPH E. M KINNEY BY %M/Mrz4w ATTORNEYS United States Patent US. Cl. 292-241 Claims ABSTRACT OF THE DISCLOSURE A latch assembly for a hinged side door in a bin for bulk materials wherein a split sleeve is assembled with a latch bolt so that when the door is latched, a tight seal is provided around the latch bolt to prevent leakage of the bin contents.

The principal'object of this invention is to provide a side door discharge bin with an improved door latch assembly.

'One of the most diflicult areas to seal in a side door discharge bin of the type disclosed in US. Pat. No. 2,648,- 428 is in the area of the side door latch assembly. The usual sealing materials assembled with the latch bolt tend to expand and shrink in response to varying humidity conditions resulting in a slight leakage around the latch bolt. Inserts, formed of nylon, have been positioned around the latch bolt, but did not prevent leakage either through the insert or around the insert. Attempts have also been made to eliminate this leakage by assembling the well known O-rings with the latch bolt, but this approach has not been successful.

In the improved latch assembly of this invention, a generally cup shaped boss is mounted on and extended through the bin side door, the boss having a tubular side wall and an end wall disposed within the bin in the closed position of the door. A latch bolt extends through the boss end wall so that the head of the bolt is located outside the bin and a latching cam on the bolt is disposed inside the bin. A tubular split sleeve unit is mounted on the bolt at a position such that the sleeve unit is engaged axially between the bolt head and the boss end wall. The sleeve is split so that it consists of two axially adjacent sections having interfitting frusto-conical end surfaces which are movable in radially opposite directions in response to an axial force on the sleeve unit. When the latch bolt is rotated in the boss to engage the latch cam with the usual latch plate inside the bin, an axial force is applied to the head of the bolt which is transmitted to the split sleeve unit so as to cause the desired radial movement of the frusto-conical end surfaces on the surfaces on the sleeve sections. This movement insures a positive seal between the latch bolt and the sleeve and between the sleeve and the boss to thereby preclude any possibility of leakage of the bin contents around the latch bolt.

Further objects, features and advantages of this invention will become apparent from a consideration of the following description, the appended claims, and the accompanying drawing in which:

FIG. 1 is a foreshortened front view of a side door discharge bin provided with the improved latch assembly of this invention;

FIG. 2 is an enlarged fragmentary sectional view of the latch assembly of this invention as seen from substantially the line 22 in FIG 1; and

FIG. 3 is a transverse sectional view of a portion of the latch assembly of this invention looking along the line 33 in FIG. 2.

With reference to the drawing, the improved latch assembly of this invention, indicated generally at in 3,567,263 Patented Mar. 2, 1971 FIG. 2, is illustrated in FIG. 1 in assembly relation with a side door discharge bin 12 having a top fill door or cover 14 and a side discharge door 16 secured by a hinge assembly 18 to a bin side wall 20. The bin 12 also has a bottom wall 22 (FIG. 2) on which the usual latch plate 24 is mounted in a fixed position.

The side door 16 has a reinforcing plate 26 secured to the outer surface 28 thereof, and a generally cup shape boss member 30 is mounted on the door 16 so that it extends through both the reinforcing plate 26 and the door 16. An internal weld 32 and an external weld 34 are employed around the periphery of the boss 30 to insure a mounting of the boss 30 in a fixed position on the door 16 in which leakage of the bin contents around the boss 30 is prevented. The boss 30 has a tubular side wall 36 and an end wall 38 disposed within the bin 12 in the closed position of the door 16 illustrated in FIG. 2.

A latch bolt 40 extends axially through the boss 30 and through an opening '42 in the boss end wall 38 and has a helical latch cam 44, of well known construction, mounted on its inner end and maintained in a fixed position thereon by a nut 46. As shown in FIG. 2, the latch bolt 40 is formed with a shoulder 48 intermediate its ends and a plastic washer 50 is mounted on the latch bolt 40 adjacent the shoulder 48 so that when the nut 46 is tightened so as to force the latch cam 44 tightly against the shoulder 48, the washer 50 is compresesed between the boss end wall 38 and the cam 44.

The latch bolt 40 is provided on its outer end with an enlarged head 52, and a tubular split sleeve unit 54 is positioned on the latch bolt 40 adjacent the head 52. As shown in FIG. 2, the sleeve unit 44 is of a length such that it is engaged at its ends with the boss end wall 38 and the latch bolt head 52, and the sleeve unit 54 is of a thickness such that it is engaged radially between the boss side wall 36 and the bolt 40.

The tubular sleeve unit 54 is formed of a plastic material having low friction characteristics, such as nylon, and is split so that it consists of two tubular sections 56 and 58. The inner end of the sleeve section 56 is formed with a generally frusto-conical external surface 60 which is inclined at the same angle as an internal frusto-conical surface 62 formed on the inner end of the sleeve section 58. These frusto-conical surfaces 60 and 62 are engaged, as shown in FIG. 2, so that when the sleeve unit 54 is axially compressed between the boss end wall 38 and the bolt head 52, a force is applied to the surface 60 tending to move the inner end of the sleeve section 56 radially inwardly and a similar force is applied to the surface 62 tending to move the inner end of the sleeve section 58 radially outwardly. This provides for a tight seal of the inner end of the sleeve section 56 against the bolt 40 and a similar tight seal between the sleeve section 58 and the tubular boss side wall 36. These tight seals prevent any leakage either through the sleeve unit 54 or around the sleeve unit 54.

In the operation of the latch assembly 10, when the door 16 is moved from an open position to a closed position, the latch cam 44 clears the latch plate 24. The door 1 6 is moved to a position in which the lower edge of the door engages the bin side wall 22, and a suitable wrench or the like is applied to the bolt head 52 so as to rotate the bolt 40 and apply the cam 44 to the latch plate 24. As the cam 44 is progressively applied to the latch plate 24, a force is transmitted by the latch cam 44 through the latch bolt 40 to the bolt head 52, with this force being directed inwardly of the bin 12. This force at the latch bolt head 52 provides for the desired axial compression of the split sleeve unit 54 between the boss end wall 38 and the latch bolt head 52. As a result, as the bolt 40 is rotated to progressively tighten the engagement of the cam plate 44 with the latch plate 24, the desired seal between the split sleeve unit 54 and the latch bolt 40 and the boss 30 is progressively increased. The provision of the Washer 50 also contributes to the desired seal since it reduces the amount of the bin contents which might come in contact with the latch bolt 40. Consequently, when the bin 12 is subsequently filled with bulk material, leakage of this material around the latch bolt 40 is positively precluded.

It will be understood that the door latch assembly for side door discharge bins which is herein disclosed and described is presented for purposes of explanation and illustration and is not intended to indicate limits of the invention, the scope of which is defined by the following claims.

What is claimed is:

1. In a bin for transporting and storing bulk material and having a side wall discharge opening and a hinged side door for closing said opening, a door latch assembly comprising a latch plate mounted in a fixed position in said bin adjacent said opening, a generally cup shape boss secured to and extending through said door, said boss having a tubular side wall and an end wall disposed within said bin in the closed position of said door, a latch bolt extending through said boss end wall and having a head located outside said bin, a tubular sleeve unit mounted on said bolt and engaged radially between said bolt and said boss and engaged axially between said bolt head and said boss end Wall, cam means on said bolt engageable with said latch plate in the closed position of said door and operable in response to rotation of said bolt to apply an axial force to said bolt head directed inwardly of said bin, said sleeve unit consisting of a pair of axially adjacent sections having abutting ends configured to provide for the application of a radially inwardly directed compressing force to one section and a radially outwardly directed compressing force to the outer section in response to said axial force on said bolt head to thereby provide a seal between said bolt and said boss in the closed position of said door.

2. The structure according to claim 1 wherein said ends of said sleeve sections are inclined relative to the longitudinal axis of said bolt.

3. The structure according to claim 2 wherein one of said sleeve section ends extends to a position radially within the other sleeve section end.

4. The structure according to claim 51 wherein one of said sleeve section ends has an outer frusto-conical surface and the other one of said sleeve section ends has an inner frusto-conical surface engaged with said outer frustoconical surface.

5. The structure according to claim 4 wherein said sleeve sections are formed of a plastic material having low friction characteristics enabling said frusto-conical surfaces to slide relative to each other.

References Cited UNITED STATES PATENTS 2,120,039 6/1938 Payne 292--356 2,506,553 5/1950 Slaughter, Jr., et al. 292240 3,130,855 4/1964 Gunn, Jr. 292--240X FOREIGN PATENTS 1,102,582 10/1955 France 277l RICHARD E. MOORE, Primary Examiner 

